I have, since my youth, been embarrassed about the size of my dick. It is about 5 inches long, and quite thin when erect. I married a small woman, hoping that would compensate for my lack of size. We had a very good sex life, but I was still insecure. My wife had never had an orgasm with my dick, but I always gave her a lot of oral sex, which she liked, but needed more than any woman I have ever heard of. I have had a couple of experiences that have made my self-esteem much worse. But the biggest problem is my very confused feelings between insecurity, hurt, and excitement. Here is the story.My wife and I were at a friend's house to visit. They have a swimming pool, and had invited us to come over for a swim. Bill's wife had taken her kids somewhere, so it was just Bill, my wife and I. I have always known that my wife had an attraction to Bill. I don't think he is all that good looking, but some women seem to think so. He is about 5'8'', and has a soft, somewhat heavy body. He has a very hairy chest, which my wife has commented on favorably. My wife was sunbathing, I had just gotten out of the water, and Bill was still in the pool. When he finally got out, I happened to look at my wife to see what she was doing. She had a look of shock on her face. I followed her gaze to see what she was staring at. Bill was wearing a typical bathing suit, which was light colored. He appeared to be extremely well endowed. I looked back at my wife, who was still staring at his huge endowment. I don't know who was more stunned, her or me. My wife and I did not talk about this, because even though she had a much stronger sex drive than I do, she doesn't like to talk about sexual things. I was also insecure about her sexual drive, and ability to get ready and orgasm so much more than I can. As embarrassed as I was about seeing Bill's big cock, I also felt a strange sense of excitement, that I still do not understand.Then things got much worse. I had been wondering if something was going on between my wife and Bill, based on some of her behavior. Well, he invited us over to swim again, and again his wife was not home. After swimming, I had gone into their pool house to change from my swim suit to my street clothes. Bill walked in just after me, when I had my trunks off, and was drying off. He said "wow, you must really be cold". I said, "no, why do you think so". He said "well because your dick looks so shriveled up and small". Then he caught himself, and said, "well I'm sure it's just because of the cold water, I'm sure it gets much bigger when you're not so cold." I had never talked about my size to anyone, but said "well, not really." There was a long silence, and I again noticed how very large his cock looked in his trunks. I soothed myself by thinking that the inside netting must have been holding his cock in such a way that it looked bigger than it really was. It couldn't have been that big. As I am thinking all of this, Bill removed his trunks, and I was amazed. Completely soft, it was much longer, and especially thicker than mine is hard. He walked over to get his own shorts, and as he walked back towards me, I realized that he had been in the cold water too, and as he was beginning to warm up, he got even larger. His big soft cock was swinging back and forth from the weight. He said, "well, don't worry, I'm sure it gets much larger when hard, and that's the most important to the ladies." I was staring at the floor, and trying not to stare at his cock, and I was too embarrassed to answer. He said "well it does get a lot larger doesn't it?" As I looked over at his amazing endowment, I blurted out "well, NOTHING like THAT." I felt so humiliated, but amazed by his size. I apologized for staring, but said I had never seen anything like it.Bill could see that I was very embarrassed, and said, "well, it's not like I haven't gotten that reaction from guys before. When I was in high school, all the football players would tease me about it, but they also stared alot. A couple of them started to get hard, but turned away quickly so no one would notice. A couple of them asked me to play helicopter." Being naive I asked what is that? Bill laughed, and started swinging his cock around like a helicopter blade, and it got ever larger. My shock, and strange excitement over-ruled my embarrassment, and insecurity. I blurted out "it doesn't get any bigger when you are hard though does it?" He said, of course, because it's completely soft now. I asked how much bigger does it get? I couldn't believe I was asking this of a male friend, especially one who I thought might be having an affair with my wife. Bill said, "I wish I had a dollar for every time someone asked my that." I could feel my face turn red and said sorry. Bill just put his hands on his hips and smiled. He then said, "a picture is worth a thousand words. Within seconds, his cock started to rise, and I was as shocked by his ability to get hard instantly, as I was by how huge his cock was. I stared in amazement, and said, "I can't believe any woman could take a cock that big." He hesitated, then said, "there is one woman I have been with that although she is a quite small person, seems enthralled by my size. I can't get much of it inside her, but once just the head of it is in her, she starts having multiple orgasms. She loves to run her fingers through my chest hair, and is very loud when she cums, and it seems like she will never stop, which is fine with me." She makes a strange sound like eeeee, then aaaaaaa. He said, I have never heard a woman cum that many times. She said that her husband's dick is small, and thin, so I guess she is pretty amazed by my size.By this time, it is obvious to me, that he is talking about my wife. I am shocked, hurt, embarrassed, angry, and turned on all at the same time. I look again at his immense cock, and staring at it, feel like maybe this is what she has wanted and needed for our entire marriage.Eventually, my wife told me of the affair, and said, "I love you, but it is just sexual with Bill, and he satisfies me more than I can possibly explain" When I asked her if he had a large cock, she said, "you really don't want to know."Unfortunately, I have the picture of Bill's impossibly large cock permanently embedded in my brain. By far, my greatest sexual turn on is thinking of Bill's huge cock in my wife, giving her more pleasure than I could possibly imagine. I also get a strange turn on thinking of her comparing his cock with mine. She has been unwilling to do so, but if I ask her, sometimes she will make a little joke about my "little one". This turns me on. I guess that sometimes our greatest pain, and fear can become our greatest sexual excitement.